An open vertical wind tunnel

An open vertical wind tunnel comprising:

• a frame structure, wherein at least some sections between beams of the frame structure are covered by perforated metal plates and a hollow volume in the frame structure enclosed by the perforated metal plates is filed with sound absorbing material;
• a power unit attached to the frame structure;
• a fan assembly;
• a flow straightening assembly comprising:
• a vertical cylindrical housing mounted above and coaxially with the fan assembly, wherein a part of an inner surface of the vertical cylindrical housing is inclined and perforated, and a hollow volume in the vertical cylindrical housing is filled with sound absorbing material;
• a central cone disposed within and coaxially with the vertical cylindrical housing, wherein a lateral surface of said central cone is perforated and a hollow volume in said central cone is filled with sound absorbing material;
• and
• a plurality of radially oriented vertically disposed guide vanes, wherein each guide vane (44) is attached to an inner surface of the vertical cylindrical housing and the central cone;
• and
• a flight platform comprising a safety net and safety cushion there around, and wherein the guide vane comprises a curved leading section and straight trailing section as integral parts of the guide vane and the guide vane from both of its sides is covered by a perforated metal sheet forming perforated shell of the guide vane, wherein a curved leading section is aerodynamically formed to be able to receive a whirling airflow generated by the fan assembly and guide said airflow to the straight trailing section straightening said airflow parallel with the central axis of the flow straightening assembly.